Using a production key on Mandrill I am attempting to send an email. Previously this has worked without issue. However now, despite receiving a successful response from the API, visible in the api log, no email is being sent, and nothing is present in the outbound activity log.
If I check the api log for the message which appeared to fail it displays:
[
{
"email": [email_address],
"status": "sent",
"_id": [id],
"reject_reason": null
}
]
Replacing the id in the content view of a sent email, with the id from a failed one displays a correctly formatted email:
e.g. https://mandrillapp.com/activity/content?id=20151214_[put_the_id_here]
Is this a bug? What is causing it? Where can I see more information about what happened? How can I monitor if this happens again in the future? How can I prevent it from happening in the future?
I have been in contact with Mandrill support regarding the issue, which they described as 'very strange indeed'. Deleting the API key and generating a new one fixed the issue, but there is no explanation as to why this is they case, how to detect the problem, or how to stop it from happening again in the future.
The messages in question were never actually sent by Mandrill, and displayed no SMTP events, despite reporting as sent by their API